513 lines
24 KiB
PHP
513 lines
24 KiB
PHP
<?php
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/////////////////////////////////////////////////////////////////
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/// getID3() by James Heinrich <info@getid3.org> //
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// available at http://getid3.sourceforge.net //
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// or http://www.getid3.org //
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/////////////////////////////////////////////////////////////////
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// See readme.txt for more details //
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/////////////////////////////////////////////////////////////////
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// //
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// module.audio.aac.php //
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// module for analyzing AAC Audio files //
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// dependencies: NONE //
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// ///
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/////////////////////////////////////////////////////////////////
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class getid3_aac extends getid3_handler
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{
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public function Analyze() {
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$info = &$this->getid3->info;
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fseek($this->getid3->fp, $info['avdataoffset'], SEEK_SET);
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if (fread($this->getid3->fp, 4) == 'ADIF') {
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$this->getAACADIFheaderFilepointer();
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} else {
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$this->getAACADTSheaderFilepointer();
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}
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return true;
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}
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public function getAACADIFheaderFilepointer() {
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$info = &$this->getid3->info;
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$info['fileformat'] = 'aac';
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$info['audio']['dataformat'] = 'aac';
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$info['audio']['lossless'] = false;
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fseek($this->getid3->fp, $info['avdataoffset'], SEEK_SET);
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$AACheader = fread($this->getid3->fp, 1024);
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$offset = 0;
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if (substr($AACheader, 0, 4) == 'ADIF') {
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// http://faac.sourceforge.net/wiki/index.php?page=ADIF
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// http://libmpeg.org/mpeg4/doc/w2203tfs.pdf
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// adif_header() {
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// adif_id 32
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// copyright_id_present 1
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// if( copyright_id_present )
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// copyright_id 72
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// original_copy 1
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// home 1
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// bitstream_type 1
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// bitrate 23
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// num_program_config_elements 4
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// for (i = 0; i < num_program_config_elements + 1; i++ ) {
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// if( bitstream_type == '0' )
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// adif_buffer_fullness 20
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// program_config_element()
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// }
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// }
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$AACheaderBitstream = getid3_lib::BigEndian2Bin($AACheader);
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$bitoffset = 0;
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$info['aac']['header_type'] = 'ADIF';
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$bitoffset += 32;
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$info['aac']['header']['mpeg_version'] = 4;
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$info['aac']['header']['copyright'] = (bool) (substr($AACheaderBitstream, $bitoffset, 1) == '1');
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$bitoffset += 1;
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if ($info['aac']['header']['copyright']) {
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$info['aac']['header']['copyright_id'] = getid3_lib::Bin2String(substr($AACheaderBitstream, $bitoffset, 72));
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$bitoffset += 72;
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}
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$info['aac']['header']['original_copy'] = (bool) (substr($AACheaderBitstream, $bitoffset, 1) == '1');
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$bitoffset += 1;
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$info['aac']['header']['home'] = (bool) (substr($AACheaderBitstream, $bitoffset, 1) == '1');
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$bitoffset += 1;
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$info['aac']['header']['is_vbr'] = (bool) (substr($AACheaderBitstream, $bitoffset, 1) == '1');
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$bitoffset += 1;
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if ($info['aac']['header']['is_vbr']) {
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$info['audio']['bitrate_mode'] = 'vbr';
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$info['aac']['header']['bitrate_max'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 23));
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$bitoffset += 23;
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} else {
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$info['audio']['bitrate_mode'] = 'cbr';
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$info['aac']['header']['bitrate'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 23));
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$bitoffset += 23;
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$info['audio']['bitrate'] = $info['aac']['header']['bitrate'];
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}
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if ($info['audio']['bitrate'] == 0) {
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$info['error'][] = 'Corrupt AAC file: bitrate_audio == zero';
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return false;
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}
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$info['aac']['header']['num_program_configs'] = 1 + getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
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$bitoffset += 4;
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for ($i = 0; $i < $info['aac']['header']['num_program_configs']; $i++) {
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// http://www.audiocoding.com/wiki/index.php?page=program_config_element
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// buffer_fullness 20
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// element_instance_tag 4
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// object_type 2
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// sampling_frequency_index 4
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// num_front_channel_elements 4
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// num_side_channel_elements 4
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// num_back_channel_elements 4
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// num_lfe_channel_elements 2
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// num_assoc_data_elements 3
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// num_valid_cc_elements 4
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// mono_mixdown_present 1
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// mono_mixdown_element_number 4 if mono_mixdown_present == 1
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// stereo_mixdown_present 1
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// stereo_mixdown_element_number 4 if stereo_mixdown_present == 1
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// matrix_mixdown_idx_present 1
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// matrix_mixdown_idx 2 if matrix_mixdown_idx_present == 1
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// pseudo_surround_enable 1 if matrix_mixdown_idx_present == 1
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// for (i = 0; i < num_front_channel_elements; i++) {
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// front_element_is_cpe[i] 1
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// front_element_tag_select[i] 4
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// }
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// for (i = 0; i < num_side_channel_elements; i++) {
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// side_element_is_cpe[i] 1
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// side_element_tag_select[i] 4
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// }
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// for (i = 0; i < num_back_channel_elements; i++) {
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// back_element_is_cpe[i] 1
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// back_element_tag_select[i] 4
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// }
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// for (i = 0; i < num_lfe_channel_elements; i++) {
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// lfe_element_tag_select[i] 4
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// }
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// for (i = 0; i < num_assoc_data_elements; i++) {
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// assoc_data_element_tag_select[i] 4
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// }
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// for (i = 0; i < num_valid_cc_elements; i++) {
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// cc_element_is_ind_sw[i] 1
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// valid_cc_element_tag_select[i] 4
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// }
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// byte_alignment() VAR
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// comment_field_bytes 8
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// for (i = 0; i < comment_field_bytes; i++) {
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// comment_field_data[i] 8
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// }
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if (!$info['aac']['header']['is_vbr']) {
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$info['aac']['program_configs'][$i]['buffer_fullness'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 20));
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$bitoffset += 20;
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}
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$info['aac']['program_configs'][$i]['element_instance_tag'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
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$bitoffset += 4;
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$info['aac']['program_configs'][$i]['object_type'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 2));
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$bitoffset += 2;
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$info['aac']['program_configs'][$i]['sampling_frequency_index'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
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$bitoffset += 4;
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$info['aac']['program_configs'][$i]['num_front_channel_elements'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
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$bitoffset += 4;
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$info['aac']['program_configs'][$i]['num_side_channel_elements'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
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$bitoffset += 4;
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$info['aac']['program_configs'][$i]['num_back_channel_elements'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
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$bitoffset += 4;
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$info['aac']['program_configs'][$i]['num_lfe_channel_elements'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 2));
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$bitoffset += 2;
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$info['aac']['program_configs'][$i]['num_assoc_data_elements'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 3));
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$bitoffset += 3;
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$info['aac']['program_configs'][$i]['num_valid_cc_elements'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
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$bitoffset += 4;
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$info['aac']['program_configs'][$i]['mono_mixdown_present'] = (bool) getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
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$bitoffset += 1;
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if ($info['aac']['program_configs'][$i]['mono_mixdown_present']) {
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$info['aac']['program_configs'][$i]['mono_mixdown_element_number'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
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$bitoffset += 4;
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}
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$info['aac']['program_configs'][$i]['stereo_mixdown_present'] = (bool) getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
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$bitoffset += 1;
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if ($info['aac']['program_configs'][$i]['stereo_mixdown_present']) {
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$info['aac']['program_configs'][$i]['stereo_mixdown_element_number'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
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$bitoffset += 4;
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}
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$info['aac']['program_configs'][$i]['matrix_mixdown_idx_present'] = (bool) getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
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$bitoffset += 1;
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if ($info['aac']['program_configs'][$i]['matrix_mixdown_idx_present']) {
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$info['aac']['program_configs'][$i]['matrix_mixdown_idx'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 2));
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$bitoffset += 2;
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$info['aac']['program_configs'][$i]['pseudo_surround_enable'] = (bool) getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
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$bitoffset += 1;
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}
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for ($j = 0; $j < $info['aac']['program_configs'][$i]['num_front_channel_elements']; $j++) {
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$info['aac']['program_configs'][$i]['front_element_is_cpe'][$j] = (bool) getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
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$bitoffset += 1;
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$info['aac']['program_configs'][$i]['front_element_tag_select'][$j] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
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$bitoffset += 4;
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}
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for ($j = 0; $j < $info['aac']['program_configs'][$i]['num_side_channel_elements']; $j++) {
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$info['aac']['program_configs'][$i]['side_element_is_cpe'][$j] = (bool) getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
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$bitoffset += 1;
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$info['aac']['program_configs'][$i]['side_element_tag_select'][$j] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
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$bitoffset += 4;
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}
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for ($j = 0; $j < $info['aac']['program_configs'][$i]['num_back_channel_elements']; $j++) {
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$info['aac']['program_configs'][$i]['back_element_is_cpe'][$j] = (bool) getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
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$bitoffset += 1;
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$info['aac']['program_configs'][$i]['back_element_tag_select'][$j] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
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$bitoffset += 4;
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}
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for ($j = 0; $j < $info['aac']['program_configs'][$i]['num_lfe_channel_elements']; $j++) {
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$info['aac']['program_configs'][$i]['lfe_element_tag_select'][$j] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
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$bitoffset += 4;
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}
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for ($j = 0; $j < $info['aac']['program_configs'][$i]['num_assoc_data_elements']; $j++) {
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$info['aac']['program_configs'][$i]['assoc_data_element_tag_select'][$j] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
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$bitoffset += 4;
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}
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for ($j = 0; $j < $info['aac']['program_configs'][$i]['num_valid_cc_elements']; $j++) {
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$info['aac']['program_configs'][$i]['cc_element_is_ind_sw'][$j] = (bool) getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
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$bitoffset += 1;
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$info['aac']['program_configs'][$i]['valid_cc_element_tag_select'][$j] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
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$bitoffset += 4;
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}
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$bitoffset = ceil($bitoffset / 8) * 8;
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$info['aac']['program_configs'][$i]['comment_field_bytes'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 8));
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$bitoffset += 8;
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$info['aac']['program_configs'][$i]['comment_field'] = getid3_lib::Bin2String(substr($AACheaderBitstream, $bitoffset, 8 * $info['aac']['program_configs'][$i]['comment_field_bytes']));
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$bitoffset += 8 * $info['aac']['program_configs'][$i]['comment_field_bytes'];
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$info['aac']['header']['profile'] = self::AACprofileLookup($info['aac']['program_configs'][$i]['object_type'], $info['aac']['header']['mpeg_version']);
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$info['aac']['program_configs'][$i]['sampling_frequency'] = self::AACsampleRateLookup($info['aac']['program_configs'][$i]['sampling_frequency_index']);
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$info['audio']['sample_rate'] = $info['aac']['program_configs'][$i]['sampling_frequency'];
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$info['audio']['channels'] = self::AACchannelCountCalculate($info['aac']['program_configs'][$i]);
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if ($info['aac']['program_configs'][$i]['comment_field']) {
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$info['aac']['comments'][] = $info['aac']['program_configs'][$i]['comment_field'];
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}
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}
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$info['playtime_seconds'] = (($info['avdataend'] - $info['avdataoffset']) * 8) / $info['audio']['bitrate'];
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$info['audio']['encoder_options'] = $info['aac']['header_type'].' '.$info['aac']['header']['profile'];
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return true;
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} else {
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unset($info['fileformat']);
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unset($info['aac']);
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$info['error'][] = 'AAC-ADIF synch not found at offset '.$info['avdataoffset'].' (expected "ADIF", found "'.substr($AACheader, 0, 4).'" instead)';
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return false;
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}
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}
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public function getAACADTSheaderFilepointer($MaxFramesToScan=1000000, $ReturnExtendedInfo=false) {
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$info = &$this->getid3->info;
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// based loosely on code from AACfile by Jurgen Faul <jfaul<75>gmx.de>
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// http://jfaul.de/atl or http://j-faul.virtualave.net/atl/atl.html
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// http://faac.sourceforge.net/wiki/index.php?page=ADTS // dead link
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// http://wiki.multimedia.cx/index.php?title=ADTS
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// * ADTS Fixed Header: these don't change from frame to frame
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// syncword 12 always: '111111111111'
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// ID 1 0: MPEG-4, 1: MPEG-2
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// MPEG layer 2 If you send AAC in MPEG-TS, set to 0
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// protection_absent 1 0: CRC present; 1: no CRC
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// profile 2 0: AAC Main; 1: AAC LC (Low Complexity); 2: AAC SSR (Scalable Sample Rate); 3: AAC LTP (Long Term Prediction)
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// sampling_frequency_index 4 15 not allowed
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// private_bit 1 usually 0
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// channel_configuration 3
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// original/copy 1 0: original; 1: copy
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// home 1 usually 0
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// emphasis 2 only if ID == 0 (ie MPEG-4) // not present in some documentation?
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// * ADTS Variable Header: these can change from frame to frame
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// copyright_identification_bit 1
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// copyright_identification_start 1
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// aac_frame_length 13 length of the frame including header (in bytes)
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// adts_buffer_fullness 11 0x7FF indicates VBR
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// no_raw_data_blocks_in_frame 2
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// * ADTS Error check
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// crc_check 16 only if protection_absent == 0
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$byteoffset = $info['avdataoffset'];
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$framenumber = 0;
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// Init bit pattern array
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static $decbin = array();
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// Populate $bindec
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for ($i = 0; $i < 256; $i++) {
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$decbin[chr($i)] = str_pad(decbin($i), 8, '0', STR_PAD_LEFT);
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}
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// used to calculate bitrate below
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$BitrateCache = array();
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while (true) {
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// breaks out when end-of-file encountered, or invalid data found,
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// or MaxFramesToScan frames have been scanned
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if (!getid3_lib::intValueSupported($byteoffset)) {
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$info['warning'][] = 'Unable to parse AAC file beyond '.ftell($this->getid3->fp).' (PHP does not support file operations beyond '.round(PHP_INT_MAX / 1073741824).'GB)';
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return false;
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}
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fseek($this->getid3->fp, $byteoffset, SEEK_SET);
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// First get substring
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$substring = fread($this->getid3->fp, 9); // header is 7 bytes (or 9 if CRC is present)
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$substringlength = strlen($substring);
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if ($substringlength != 9) {
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$info['error'][] = 'Failed to read 7 bytes at offset '.(ftell($this->getid3->fp) - $substringlength).' (only read '.$substringlength.' bytes)';
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return false;
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}
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// this would be easier with 64-bit math, but split it up to allow for 32-bit:
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$header1 = getid3_lib::BigEndian2Int(substr($substring, 0, 2));
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$header2 = getid3_lib::BigEndian2Int(substr($substring, 2, 4));
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$header3 = getid3_lib::BigEndian2Int(substr($substring, 6, 1));
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$info['aac']['header']['raw']['syncword'] = ($header1 & 0xFFF0) >> 4;
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if ($info['aac']['header']['raw']['syncword'] != 0x0FFF) {
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$info['error'][] = 'Synch pattern (0x0FFF) not found at offset '.(ftell($this->getid3->fp) - $substringlength).' (found 0x0'.strtoupper(dechex($info['aac']['header']['raw']['syncword'])).' instead)';
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//if ($info['fileformat'] == 'aac') {
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// return true;
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//}
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unset($info['aac']);
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return false;
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}
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// Gather info for first frame only - this takes time to do 1000 times!
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if ($framenumber == 0) {
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$info['aac']['header_type'] = 'ADTS';
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$info['fileformat'] = 'aac';
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$info['audio']['dataformat'] = 'aac';
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$info['aac']['header']['raw']['mpeg_version'] = ($header1 & 0x0008) >> 3;
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$info['aac']['header']['raw']['mpeg_layer'] = ($header1 & 0x0006) >> 1;
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$info['aac']['header']['raw']['protection_absent'] = ($header1 & 0x0001) >> 0;
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$info['aac']['header']['raw']['profile_code'] = ($header2 & 0xC0000000) >> 30;
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$info['aac']['header']['raw']['sample_rate_code'] = ($header2 & 0x3C000000) >> 26;
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$info['aac']['header']['raw']['private_stream'] = ($header2 & 0x02000000) >> 25;
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$info['aac']['header']['raw']['channels_code'] = ($header2 & 0x01C00000) >> 22;
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$info['aac']['header']['raw']['original'] = ($header2 & 0x00200000) >> 21;
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$info['aac']['header']['raw']['home'] = ($header2 & 0x00100000) >> 20;
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$info['aac']['header']['raw']['copyright_stream'] = ($header2 & 0x00080000) >> 19;
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$info['aac']['header']['raw']['copyright_start'] = ($header2 & 0x00040000) >> 18;
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$info['aac']['header']['raw']['frame_length'] = ($header2 & 0x0003FFE0) >> 5;
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$info['aac']['header']['mpeg_version'] = ($info['aac']['header']['raw']['mpeg_version'] ? 2 : 4);
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$info['aac']['header']['crc_present'] = ($info['aac']['header']['raw']['protection_absent'] ? false: true);
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$info['aac']['header']['profile'] = self::AACprofileLookup($info['aac']['header']['raw']['profile_code'], $info['aac']['header']['mpeg_version']);
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$info['aac']['header']['sample_frequency'] = self::AACsampleRateLookup($info['aac']['header']['raw']['sample_rate_code']);
|
||
$info['aac']['header']['private'] = (bool) $info['aac']['header']['raw']['private_stream'];
|
||
$info['aac']['header']['original'] = (bool) $info['aac']['header']['raw']['original'];
|
||
$info['aac']['header']['home'] = (bool) $info['aac']['header']['raw']['home'];
|
||
$info['aac']['header']['channels'] = (($info['aac']['header']['raw']['channels_code'] == 7) ? 8 : $info['aac']['header']['raw']['channels_code']);
|
||
if ($ReturnExtendedInfo) {
|
||
$info['aac'][$framenumber]['copyright_id_bit'] = (bool) $info['aac']['header']['raw']['copyright_stream'];
|
||
$info['aac'][$framenumber]['copyright_id_start'] = (bool) $info['aac']['header']['raw']['copyright_start'];
|
||
}
|
||
|
||
if ($info['aac']['header']['raw']['mpeg_layer'] != 0) {
|
||
$info['warning'][] = 'Layer error - expected "0", found "'.$info['aac']['header']['raw']['mpeg_layer'].'" instead';
|
||
}
|
||
if ($info['aac']['header']['sample_frequency'] == 0) {
|
||
$info['error'][] = 'Corrupt AAC file: sample_frequency == zero';
|
||
return false;
|
||
}
|
||
|
||
$info['audio']['sample_rate'] = $info['aac']['header']['sample_frequency'];
|
||
$info['audio']['channels'] = $info['aac']['header']['channels'];
|
||
}
|
||
|
||
$FrameLength = ($header2 & 0x0003FFE0) >> 5;
|
||
|
||
if (!isset($BitrateCache[$FrameLength])) {
|
||
$BitrateCache[$FrameLength] = ($info['aac']['header']['sample_frequency'] / 1024) * $FrameLength * 8;
|
||
}
|
||
getid3_lib::safe_inc($info['aac']['bitrate_distribution'][$BitrateCache[$FrameLength]], 1);
|
||
|
||
$info['aac'][$framenumber]['aac_frame_length'] = $FrameLength;
|
||
|
||
$info['aac'][$framenumber]['adts_buffer_fullness'] = (($header2 & 0x0000001F) << 6) & (($header3 & 0xFC) >> 2);
|
||
if ($info['aac'][$framenumber]['adts_buffer_fullness'] == 0x07FF) {
|
||
$info['audio']['bitrate_mode'] = 'vbr';
|
||
} else {
|
||
$info['audio']['bitrate_mode'] = 'cbr';
|
||
}
|
||
$info['aac'][$framenumber]['num_raw_data_blocks'] = (($header3 & 0x03) >> 0);
|
||
|
||
if ($info['aac']['header']['crc_present']) {
|
||
//$info['aac'][$framenumber]['crc'] = getid3_lib::BigEndian2Int(substr($substring, 7, 2);
|
||
}
|
||
|
||
if (!$ReturnExtendedInfo) {
|
||
unset($info['aac'][$framenumber]);
|
||
}
|
||
|
||
/*
|
||
$rounded_precision = 5000;
|
||
$info['aac']['bitrate_distribution_rounded'] = array();
|
||
foreach ($info['aac']['bitrate_distribution'] as $bitrate => $count) {
|
||
$rounded_bitrate = round($bitrate / $rounded_precision) * $rounded_precision;
|
||
getid3_lib::safe_inc($info['aac']['bitrate_distribution_rounded'][$rounded_bitrate], $count);
|
||
}
|
||
ksort($info['aac']['bitrate_distribution_rounded']);
|
||
*/
|
||
|
||
$byteoffset += $FrameLength;
|
||
if ((++$framenumber < $MaxFramesToScan) && (($byteoffset + 10) < $info['avdataend'])) {
|
||
|
||
// keep scanning
|
||
|
||
} else {
|
||
|
||
$info['aac']['frames'] = $framenumber;
|
||
$info['playtime_seconds'] = ($info['avdataend'] / $byteoffset) * (($framenumber * 1024) / $info['aac']['header']['sample_frequency']); // (1 / % of file scanned) * (samples / (samples/sec)) = seconds
|
||
if ($info['playtime_seconds'] == 0) {
|
||
$info['error'][] = 'Corrupt AAC file: playtime_seconds == zero';
|
||
return false;
|
||
}
|
||
$info['audio']['bitrate'] = (($info['avdataend'] - $info['avdataoffset']) * 8) / $info['playtime_seconds'];
|
||
ksort($info['aac']['bitrate_distribution']);
|
||
|
||
$info['audio']['encoder_options'] = $info['aac']['header_type'].' '.$info['aac']['header']['profile'];
|
||
|
||
return true;
|
||
|
||
}
|
||
}
|
||
// should never get here.
|
||
}
|
||
|
||
public static function AACsampleRateLookup($samplerateid) {
|
||
static $AACsampleRateLookup = array();
|
||
if (empty($AACsampleRateLookup)) {
|
||
$AACsampleRateLookup[0] = 96000;
|
||
$AACsampleRateLookup[1] = 88200;
|
||
$AACsampleRateLookup[2] = 64000;
|
||
$AACsampleRateLookup[3] = 48000;
|
||
$AACsampleRateLookup[4] = 44100;
|
||
$AACsampleRateLookup[5] = 32000;
|
||
$AACsampleRateLookup[6] = 24000;
|
||
$AACsampleRateLookup[7] = 22050;
|
||
$AACsampleRateLookup[8] = 16000;
|
||
$AACsampleRateLookup[9] = 12000;
|
||
$AACsampleRateLookup[10] = 11025;
|
||
$AACsampleRateLookup[11] = 8000;
|
||
$AACsampleRateLookup[12] = 0;
|
||
$AACsampleRateLookup[13] = 0;
|
||
$AACsampleRateLookup[14] = 0;
|
||
$AACsampleRateLookup[15] = 0;
|
||
}
|
||
return (isset($AACsampleRateLookup[$samplerateid]) ? $AACsampleRateLookup[$samplerateid] : 'invalid');
|
||
}
|
||
|
||
public static function AACprofileLookup($profileid, $mpegversion) {
|
||
static $AACprofileLookup = array();
|
||
if (empty($AACprofileLookup)) {
|
||
$AACprofileLookup[2][0] = 'Main profile';
|
||
$AACprofileLookup[2][1] = 'Low Complexity profile (LC)';
|
||
$AACprofileLookup[2][2] = 'Scalable Sample Rate profile (SSR)';
|
||
$AACprofileLookup[2][3] = '(reserved)';
|
||
$AACprofileLookup[4][0] = 'AAC_MAIN';
|
||
$AACprofileLookup[4][1] = 'AAC_LC';
|
||
$AACprofileLookup[4][2] = 'AAC_SSR';
|
||
$AACprofileLookup[4][3] = 'AAC_LTP';
|
||
}
|
||
return (isset($AACprofileLookup[$mpegversion][$profileid]) ? $AACprofileLookup[$mpegversion][$profileid] : 'invalid');
|
||
}
|
||
|
||
public static function AACchannelCountCalculate($program_configs) {
|
||
$channels = 0;
|
||
for ($i = 0; $i < $program_configs['num_front_channel_elements']; $i++) {
|
||
$channels++;
|
||
if ($program_configs['front_element_is_cpe'][$i]) {
|
||
// each front element is channel pair (CPE = Channel Pair Element)
|
||
$channels++;
|
||
}
|
||
}
|
||
for ($i = 0; $i < $program_configs['num_side_channel_elements']; $i++) {
|
||
$channels++;
|
||
if ($program_configs['side_element_is_cpe'][$i]) {
|
||
// each side element is channel pair (CPE = Channel Pair Element)
|
||
$channels++;
|
||
}
|
||
}
|
||
for ($i = 0; $i < $program_configs['num_back_channel_elements']; $i++) {
|
||
$channels++;
|
||
if ($program_configs['back_element_is_cpe'][$i]) {
|
||
// each back element is channel pair (CPE = Channel Pair Element)
|
||
$channels++;
|
||
}
|
||
}
|
||
for ($i = 0; $i < $program_configs['num_lfe_channel_elements']; $i++) {
|
||
$channels++;
|
||
}
|
||
return $channels;
|
||
}
|
||
|
||
}
|